/Engine/Source/Editor/EditorWidgets/Public/Filters/SAssetFilterBar.h
Handler to Populate the Add Filter Menu. Use OnFilterAssetType in Subclasses to add classes to the exclusion list
virtual void PopulateAddFilterMenu ( [UToolMenu](API\Developer\ToolMenus\UToolMenu) * Menu, [TSharedPtr](API\Runtime\Core\Templates\TSharedPtr)< [FFilterCategory](API\Developer\ToolWidgets\Filters\FFilterCategory) > MenuExpansion, FOnFilterAssetType OnFilterAssetType )